court just today, that was then, this is now. it's where we begin tonight with our justice correspondent, pete williams, at the court. pete, good evening. >> reporter: brian, here's the question about the voting rights act. it puts an extra burden on states with a history of discriminating at the polls. but does it cover the areas of the country where the problem is the worst? tonight, a bare majority of the supreme court seems to think the answer is no, and if that's the case, the law is in big trouble. ♪ >> reporter: dramatizing the high stakes, civil rights veterans passionately defended the law outside the court. >> we are not going back. we have come too far. we made too much progress to go back. >> at stake, the most important civil rights law ever passed, a response to widespread voter discrimination in the south. president johnson signed the voting rights act in 1965 at the u.s. capitol. fast forward, 48 years. >> i barack hussein obama, do solemnly swear.